Blasting cartridge



Patented May 3, 1932 FRANK H. KNEELAND, OF CHICAGO, ILLINOIS, ASSIGNORTO SAFETY MINING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION BLASTINGCARTRIDGE Application led November 22, 1929. Serial No. 409,022.

This invention is concerned with indestructible blasting cartridges ofthe type where a compressed or liquefied gas is employed as the blastingmedium. This type of cartridge usually consists of a metallic bodyhaving a gas chamber formed therein, a charge forming and chargeenergizing means, and a pressure responsive venting means;

It is an object of the invention to improve the construction and designof cartridges of this type with a view to effecting economies inmanufacture, assembling and maintenance.

More particularly, it is an object of the invention to standardizedimensions where possible and make the parts to a large extentinterchangeable;

Referring to the drawings,

Figure 1 is a view in longitudinal section of a Cartridge constructed inaccordance with the invention.

Figures 2 and 3 are views in transverse section taken along lines 2 2and 3 3 respectively of Figure 1. j

The present blasting cartridge is of the same general type as thoseheretofore produced in that it includes a body having an internal gaschamber, an electrode positioned in one end of the body and insulatedtherefrom, a discharge assembly associated with the opposite end of thebody and including a pressure responsive rupturable disc and a heaterunit disposed between and having electrical contact at its opposite endswith the electrode and rupturable disc respectively whereby to provide acircuit from the electrode through the heater and to the cartridge bodyfor energizing the heater by electricity and thereby generating heat tobr'ng about the blasting pressure within the cartridge.

The particular construction of the present cartridge includes a body 1which is formed internally with a symmetrical gas chamber 2 the oppositeends of which are bounded by inwardly extending ribs 3 and 4respectively. The outer face of the rib 3 provides a seat and sealingsurface for the pressure responsive rupturable disc 5 which is securedin place by means of the shear ring 6 and the sleevelike extension 7 ofthe discharge cap 8 which has threaded engagement with the in 50 teriorof the cartrdge body as indicated at 7. Y The discharge cap is ofconventional design and includes a plurality of radial dischargeopenings 9.

The electrode 10 which occupies a position 55 in the opposite end of thecartridge is so designed as to cooperate Wth the outer plane face of therib 4 and with theaid of an insulating and sealing disc 12 effects asealed engagement therewith. The electrode 10 is 60 reduced indiameteras indicated at 11 and extends into the gas chamber Where itprovides a support for one end of the heater unit. An annular insulatingring 12 surrounds the electrode and serves to effectively insulate thesame from the body of the cartridge. The extreme end of the cartridgebody is provided with internal threads 13 of substantially the same formand dimensions as thread 7 at the opposite end and these 70 threadscooperate with correspondingly formed threads 011 the electrode nut 14.yThis nut surrounds the outer end of the electrode and is separatedtherefrom by'means of insulatng members 15. The purpose of the ablymounted in a valve cap 18 which is secured to the extreme outer end ofthe electrode and serves to control the admissionof gas to the chargingpassages 16. A charging orifice 2() is provided in the cap 18 for thereception of a nozzle or other form of charg- It is of course necessarythat the 90 ing device.

ysubstantially identical dimensions.

valve cap 18 be insulated from the body of the cartridge and this isaccomplished by the insulating disc 19 which is interposed between thevalve cap and the electrode nut 14. The disc 19 likewise serves as asealing gasket to prevent the escape of gas around the threads whichconnect the valve cap and the electrode. In order to protecttheelectrode and the valve mechanism associated therewith there isprovided a protective cap 21 which is reduced in diameter as indicatedat 23, which reduced portion is provided with external threads designedto cooperate with the threads 13 formed internally of the cartridgebody. The end wall ofthe cap 21 is provided with a central opening 25designed to receive a suitably constructed terminal plug. A metallic cap24 is positioned to have contact with such a terminal plug and thecircuit from the plug and cap 24 is continued to the electrode throughthe medium of the metallic spring 23. It will be noted that in theabsence of a terminal plug, the member 24 is urged into engagement withthe cap 21 by means of the spring 23, thus providing a short circuitbetween the electrode and the metallic cartridge body. rIhe cap isprovided with one or more openings 26 in which may be inserted thesecond lead from a source of electricity.

Attention is directed to the fact that the opposite ends of thecartridge body are of identical construction, both as to form anddimensions. This in itself greatly simplities the operations involved inthe manufacture of the cartridge body. This feature also has theadvantage of rendering the charging and discharging units of thecartridge interchangeable as regards the opposite ends ofthe cartridgebody. It will also be noted that the threads on the discharge cap, the

electrode nut, and the protector cap are the` same and that theremaining parts are of By virtue of these several features there isprovided av blasting cartridge of inexpensive construction and onewherein the parts are sostandardized as to dimensions that all parts arereadily interchangeable.

I claim:

1. A blasting cartridgecomprising an elongated open ended cylinder, apressure responsive discharge assembly associated with one end of saidcylinder, a charging and charge energizing assembly associated with theother end of said cylinder, said assemblies sealing the respective endsof said cylinder and forming therebetween a chamber for reception of ablasting charge, said assemblies being interchangeable with reference tothe respective en ds of the cylinder.

2. A blasting cartridge comprising an open l ended cylinder internallythreaded adjacent opposite ends and having interior sealing surfacesinwardly of said threads, and means adapted to be interchangeablyassociated with f said ends and the respective sealing surfaces thereof.4

3. A blasting cartridge comprising a hollow cylinder of substantiallyuniform'wall 7| thickness throughout its length except at two points,one adjacent each end, at which points the wall thickness is increasedto form inwardly extending shoulders, the ends of said cylinder beinginternally threaded outward- 7l ly of said shoulders, and means forclosing the opposite ends of said cylinder.

Signed at Chicago, Illinois, this 19th day of November, 1929.

, FRANK I-I. KNEELAND. 8c

